


The Leóne Decimo

by Zsterwriter14



Series: Shifter Au [6]
Category: Katekyou Hitman Reborn!
Genre: Animal Attack, Aware Nana, BAMF! Skull, Cannon Divergent, Cat! Nana, Cloud wolf shifter! Skull, Denial, Dying Will Flames, F/M, Gen, Lion! Tsuna, Other Additional Tags to Be Added, Probably the only reason hes still alive, Shifter! Hibari, Shifter! Skull, Shifter!Nana, Shifter!Tsuna, There's mention of blood ?, Tsuna is kind of an animal, bamf! tsuna, shifter!AU, sorta - Freeform, working under the idea of dying will flames being a general mafia thing
Language: English
Status: In-Progress
Published: 2018-01-24
Updated: 2018-06-23
Packaged: 2019-03-08 18:18:14
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 8,646
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13463844
Author URL: https://archiveofourown.org/users/Zsterwriter14/pseuds/Zsterwriter14
Summary: In a world where one in four people can turn into an animal, Vongola still needs someone to lead them after the Nono retires. The lion waits for the blood to come to call and free the warmth that has been stolen.Things shift into motion as Reborn comes into Namimori and meets the next decimo.





	1. Enter the Lion's den

**Author's Note:**

> This is the Shifter! au take on some cannon events. Tags will be added as I think of them. For thouse who've read the other stories in the series, chapter one takes place before On uncertain terms and after human?  
> Other stories might be writtern that are side stories but still are a part of the shifter! au cannon. 
> 
> This was beta'd by my friend JustAnotherOutcast!

The lion woke that morning knowing that something was fundamentally different. The air was almost charged with a near tangible energy that spoke of imminent change, of the ties of blood finally coming to call. 

That in mind, the lion only stretched before waiting for the human-cat to bring food. Soon it would be able to go and hunt for itself, to prove it was strong to its future pride mates. _Tsuna hoped that he didn’t actually find something to hunt when he got out. It sounded a bit too messy for him..._

For now, the lion would take what it was given. The meat that the human-cat brought was enough for now. _Tsuna made a note to thank his den mother when he could talk again._

The lion’s ears flicked up at the sound of creaking wood that heralded the human-cat’s, _Kaa-san’s_ , arrival. A lazy, orange eye peaked open to see the human-cat looking at him with a plate of raw bloody meat. “ _Good morning Tsu-chan,_ ” she chirped in a fake happy tone as she walked to place the plate within reach. _Tsuna wanted to tell Kaa-san he was sorry he was stuck, that he really wanted to be Tsu-chan for her again, but since he couldn’t, he settled for rubbing against her legs as he went to eat._

The lion gave a small purr as he scent marked the human-cat before digging into the offered meat. The human-cat rubbed a familiar, _hand_ , paw over his back, lightly rubbing her claws through it’s sprouting mane. _Tsuna idly wondered if his mane would mean he would have a beard when he became Tsuna again. Manes were a sign of **lion** maturity, did it translate to human maturity?_

“ _Feel like changing today?_ ” she asked as she moved forwards to turn on the noise box, _CD player_ , filling the room with human chatter. The lion didn’t understand why the human-cay turned it on everyday, but it was outside of the reach of the chain so there was little the lion could do. _Tsuna definitely prefered to watch tv, but he felt like the shifter alternative education cds would help him not sound like he was still five._

The human-cat sighed, placing her hands on her knees for a moment before straightening. The lion looked up at her, wondering if today would be even more that just the change that grew more prominent with each passing moment. The human-cat turned towards him again and looks him in the eyes, honey brown meeting feline gold. “ _A flyer came in the mail today, Tsu-kun_ ” she started before stopping, looking askance. “ _It says I’ll make your child the new leader of tomorrow. Hah. It sounds like something for a fancy business school. It’s for a home tutor, the type of tutor I would have wanted for you. You would be in middle school right now, being a moody teenager..._ ” She let off with a sigh, rubbing her eyes, the air tinged with sorrow. 

The lion didn’t know what a _tutor_ was, but its mention almost electrified the feeling in the air. The lion wanted to insist somehow, to make sure that this _tutor_ was brought. _Tsuna worried about his den mother, torn between wanting to growl and warn her about the imminent change the lion felt, but he also did not want to worry her._

The lion lapped the rest of the meat from the tray before yawning. It wouldn’t do to worry the human-cat with unchangeable events. If the _tutor_ was a part of what was going to come today, it would find a way. 

The human-cat sighed once more before rubbing a hand sown the lion’s spine one last time. She then picked up the plate and left. 

The lion watched the human-cat leave before stalking across what room it could reach to sprawl in what little sunlight filtered in. _Tsuna wondered if he would take as many naps as he did as a lion..._ The lion could only snort as it settled into a half aware doze. The lion wouldn’t stay up waiting for the change to happen. The lion will allow it to affect it on _**it’s terms**_. 

* * *

The lion’s ears flicked up in awareness around what could only be noon. A sudden influx of _something_ started to bleed through from the first floor. The lion rose to its feet with a growl; whatever it was felt _wrong_. 

_Like fire, **too much, Too Much.** Burning, harsh, like the sun was crushed too, **too small**. _

In the face of such an unnatural feeling, the lion was the one in complete control, the warmth behind the wall flaring in an attempt to reconnect. 

The lion could hear snippets of human conversation through the floor as it tracked the too small sun. 

“ _I didn’t call-_ ,” the human-cat? 

” _-husband hired me-_ ,” A new squeaky voice chirped. 

” _Oh! So you’re here to help-_ ”. 

” _Yes, is he at-?_ ” 

” _No..._ ” A pause; they were right outside the door to the lion’s temporary den. It could only glean some meaning from the shared knowledge from _Tsuna_ , but the human chatter made some sense. 

“ _Tsuna hasn’t gone to school since he was five. Didn’t Anat- didn’t Iemitsu tell you?_ ” The lion bristled at the human-cat’s distress, the scent filtering into the den. 

“ _No, but I feel like I’ve been made unaware of many things. Why doesn’t Tsunayoshi-kun go to school?_ ” 

“ _... Maybe you should see for yourself,_ ” the human-cat said after a pause as the door creaked open. 

The lion let out another low growl as it made sure to place itself far enough from the stairs that it had room to pounce if needed. The scents of coffee, _gunpowder_. and old blood became prominent as the too small sun tried to fill the den with the wrong, _wrong_ , feeling of its harsh heat. 

The lion saw the human-cat come down the stairs first, a wary, cat-like movement now in her steps, the cat normally deep within her now coming up in defence for her kit if necessary, claws prime within paws. 

Then the lion saw _it_. 

At first glance, it looked like a human cub, chubby cheeks and small stature with large dark eyes. Then the lion could see the predatory set to its movements, the near invisible crinkle of its overcoat that hid something, the far too mature look in its eyes, and the fact the scent of blood came from _it_. The lion then noticed the crystalline buttercup yellow pacifier hanging around its neck that almost matched the yellow-orange band around its hat. 

Its eyes widened in surprise for a second before being smoothed out as it gazed at the lion, taking in the lion’s form and the chain connecting it to the wall. 

“ _Sawada-san... What is going on?_ ” the not-cub asked warily, it’s paws twitching. The lion growled again, getting a fluttery, panic, response from the _cat_ -human. 

“ _I don’t know. Tsu-kun usually isn’t this aggressive,_ ” the cat-human said as she stepped around the not-cub to go back upstairs. “ _I think he might be hungry. You can assess him to see what you’ll need to do while I get him food._ ” She then disappeared up into the house. 

The not-cub almost looked like it wanted to stop her before it looked back at the lion. The lion growled at it again, flexing its claws in warning. 

That only garnered an unimpressed look from the not-cub. Its eyes traveled over the lion’s form again as it descended the stairs, dark orbs alight with heavily veiled confusion. If the lion hadn’t smelt the confusion in the air, it probably would have doubted what it saw. 

The not-cub frowned as it finally reached the bottom step. The lion tensed, the feeling of the too small sun was radiating off the not-cub, and lion was ready to _pounce_. 

Something _green_ flitted on the brim of the not-cub’s hat. 

The not-cub stared at the lion calculatingly, as if there was something that would reveal itself if the not-cub stared long enough. 

Large yellow eyes blinked slowly from the green thing’s head. _Taunting_. 

“ _Can you understand Japanese?_ ” The not-cub asked suddenly, the lion’s eyes flickered to its own with a growl. The not-cub frowned. “ _I’m going to kill Iemitsu._ ” 

The green thing flicked its tounge out before twitching its tail. 

The lion growled lowly, teeth bared as his tail lashed. Lowering itself on to its haunches, the not-cub wasn’t even looking at the lion anymore. 

The green thing narrowed its yellow eyes, _and it **hissed. At. the Lion.**_

“ _Leon?-SHIT-_!” the not-cub shouted as the lion pounced on him, going for the green thing. The not-cub tried to move the lion as it pinned its chest with a paw, so it could catch the green thing. 

The green thing shrieked as it was pulled from the hat. 

“ _Leon!_ ” the not-cub squeaked, eyes wide in panic. 

The lion pushed off the not-cub, holding the green thing by its tail in its mouth. The lion contemplated swallowing the thing whole when the lion felt a sharp prick in its shoulder. 

The world _tilted_ suddenly, the lion’s jaw going slack. It blinked fuzzily as the not-cub scooped the little green thing up with a worried noise. 

Then the lion collapsed into an abrupt slumber. 

* * *

  


Reborn took a controlled breath while he pumped what little sun flames he had left into the slightly bleeding, shaking Leon, staring at the lion who had almost eaten his partner. It was sleeping now, the bright tufted end of a heavy duty tranquilizer dart sticking from the harvest gold fur. He turned to see the sawada matriarch standing on the stairs with a tranq gun in hand. 

Her cat-bright eyes locked on his own before he tilted his fedora down to cover his expression. “Are you alright?” She asked after a moment. 

Reborn took another moment to check over Leon before returning the chameleon to his fedora. “Ah, I’m fine, more surprised than anything Sawada-san,” he said. His sore chest and the small rips in his suit said otherwise, but he had been through worse. 

“Ah, I’m so sorry about Tsu-kun. He’s never been this aggressive towards a stranger before. It took me a while to find this,” she said cheerily enough, lifting the gun up for him to see, but her posture screamed that she was on edge, as if she _saw something_. Reborn wondered if she had seen the flames and if she was truely as oblivious as he husband thought she was... 

“...Sawada-san, do you know what’s wrong with Tsunayoshi-kun?” Reborn asked as Nana started back up the stairs. At his question, she froze before giving him a confused, if not _concerned_ , look over her shoulder at him. 

“Didn’t Iemitsu tell...you?” Nana trailed off, turning to look at him, eyes narrowing with a warriness he had been noticing off and on since he came. He wondered just how safe the sawada residence had truly been over the years of Iemitsu’s absence. _The lion’s chain could reach the bottom step of the stairs after all._

“Sawada-san, I believe Iemitsu sent me to do a very different job than you hoped he did,” Reborn said cautiously, allowing a thread of killing intent to leak out. Nana’s eyes gleamed as her pupils slimmed to feline ones before widening. Reborn wondered how many had met their end to the claws of the two felines in the house and decided that he would never put in trust in any information Iemitsu had a hand in providing without doing his own recognizance or asking Mammon. 

Nana gave him a nice smile with too many teeth, like she knew what he was thinking, a feline smile one could say, and gestures him upstairs. “We should continue this upstairs,” she almost purrs. 

He resisted the urge to swallow as he nodded, starting up the stairs. 30 percent of the population or not, Reborn disliked predatory shifters.


	2. Calling Reinforcements

**Summary for the Chapter:**

> Reborn has a talk with the Sawada Matriarch and Skull gets an unexpected phone call.

**Notes for the Chapter:**

> Beta'd by [JustAnotherOutcast](http://archiveofourown.org/users/JustAnotherOutcast)
> 
> Any and all questions are recommended to asked. I will try to answer them without spoiling anything.

The cat shifter lead him into the kitchen when he had left his suitcase before looking at him. Her eyes were no longer those of a somewhat cautious housewife, but the ones of a cat in the ace of _prey_. “Nee, Reborn-kun, what exactly did my husband hire you to teach my Tsu-kun?” she asked. He jumped onto the kitchen table with a confidence he _might_ not have actually felt. 

Reborn knew that Iemitsu had wanted Nana to be kept in the dark about his true line of work, what he was actually going to be teaching Tsunayoshi; he had vehemently insisted it to the hitman. Iemitsu also thought Nana was nothing more than an oblivious civilian, a house pet, without a cruel bone in her body. 

_Reborn knew better._

“I should reintroduce myself,” Reborn said, tilitling his fedora down, “Ciaosu, My name is Reborn, The World’s Greatest Hitman. I was contracted by Timoteo di Vongola to train the Vongola Decimo canidate, your son, to be a mafia don.” Reborn had watched Nana’s reaction to what he said; her eyes had narrowed at his title, but she inhaled sharply at the mention of Timoteo. Reborn remembered that the Nono had visited the sawada’s home once. Maybe it was connected to Tsunayoshi's condition? 

“What qualifies Tsu-kun for such a position?” Nana asked in a dangerous tone, eyes glinting. Reborn noticed how she had placed herself in front of the kitchen counter, in particular, the counter where the knives sat faux-innocently in a knife block. Reborn wondered how Iemitsu had missed the fact that he had married such a competent woman, though he suspected it was Iemitsu’s near constant absence. 

Reborn pulled out the pictures he _had_ planned to show to the civilian child to scare some awareness into him, _and to scare him for Reborn’s own enjoyment_ , and laid them on the table along with the Vongola family tree. 

“ _Nono_ , the Ninth’s heirs who would have inherited before Tsunayoshi were all killed. The eldest in a gunfight, the second drowned, and the youngest burned down to bones. Tsunayoshi is related to the first boss through Iemitsu’s side of the family. The first boss or _primo_ , Giotto di Vongola, relocated to Japan after the secondo had taken control of Vongola.” Reborn said. 

He watched Nana look over the document and pictures before looking back at Reborn, “And why can’t my husband inherit? He is already a part of the Mafia,” she said as she stared at him with the same calculating look he was giving her. Reborn was vaguely surprised she was aware of her husband’s involvement in the Mafia, but he could tell this wasn’t the first time Iemitsu’s supposedly separate life had found its way into the Sawada residence. 

“Iemitsu is the leader of CEDEF or Vongola’s external advisor and is thus unable to inherit by the _familia’s_ bylaws,” Reborn stated, fingers itching to arm himself as Nana’s expression soured. He knew rationally he could definitely overpower a civilian, _was she though_ , woman if it came to it, but he couldn’t help but be on edge. It was a instinctual response based solely on the fact she was a predatory shifter and he was just human. 

“Unable to be a father, too, it seems,” Nana said sardonically, lips twisted into a humorless smile. “I have been calling that man for eight years now, Reborn-san, begging him to send a shifter expert to help Tsuna. Eight _years_ , and he sends me you, a normal human, to help himself.” 

Reborn bristled as being called normal; he was the _best_ hitman in the world after all. But he also knew she meant his lack of an animal counterpart. He knew that he had no real expertise with shifters; it was predominantly a civilian thing, not a mafia thing. Hell, most shifters rarely interacted with normal humans outside of necessity. 

He grit his teeth as he considered what exactly he was going to do. _What could_ he offer the dangerously protective woman in front of her for her son? He needed someone who had experience with this that he could trust. Only one person came to mind. 

He was almost completely sure he was going to regret this. 

“I have an... associate... who could help your son. A shifter,” Reborn grit out even as he hid his displeasure behind the unaffected mask he had used almost his whole life. 

Nana hummed, eyes finally losing the predatory sharpness as she relaxed. Reborn suddenly felt like he had gone from possible threat to house guest. “That would be nice, Reborn-kun,” she chirped, “Though it would be wise to announce yourself and whoever you’re bringing to the Hibari’s. Namimori is their territory, after all.” 

Reborn suppressed his initial reaction of surprise and loathing towards the sheer amount of information that would have been useful to know that the report he had been given that was _lacking_ , and nodded. “Of course, Sawada-san.” 

Nana giggled one would have expected from the oblivious housewife she appeared to be, “Oh, call me mamma, Reborn-kun. You’re going to be here awhile it seems.” 

Reborn felt himself smiling slightly. “Right... Mamma.” 

She smiled again. “Let me show you Tsu-kun’s room. You can stay there until Tsu-kun’s ready to use it again,” she said, finally moving away from the counter. It was more relieving than it should have been. 

* * *

Nana lead him to Tsunayoshi’s room, a door with a fish shaped name plate on it, with a smile before leaving him in the room. 

Reborn _did not_ let out a sigh of relief as soon as he was out of her line of sight. Instead, he took notice of the room the lion would have been using in different circumstances. 

It was a child’s room; old stuffed animals, sheets with bright color patterns, and toys in a box at the end of a child sized bed. It felt like a three-dimensional photograph, a snapshot from Tsunayoshi’s life eight years ago before he had become the beast dwelling in the basement. If he had been any other man, Reborn probably would have felt bad about intruding on such a well maintained memory. As it was though, Reborn had snuck into places much more sacred (with much darker intentions) than the unused bedroom of a child. 

Reborn jumped on the bed to re-evaluate the situation now that he had the full picture. Ideally, at the moment, Reborn would have begun to integrate himself into his student’s daily life and intimidate the student through his less than normal behavior and thinly veiled threats and traps. It would have been like with Dino, except with the added benefit of being able to create his reputation with Tsunayoshi from scratch, a clean slate to build off of. 

Reborn let out an uncharacteristic sigh of regret. Sadly, that was not the case. 

Tsunayoshi was in no condition to be learning anything, and Reborn had only the surface knowledge on shifters. First, he would have to call... _ugh, Him_. Then he would probably have to call Verde to ask him for the research he had on shifters and how they interacted with flames. He himself had a few theories on Tsunayoshi’s condition, considering some all too similar behavior he noticed the lion exhibit, but Reborn wanted something solid to work off of. 

Reborn stifled a yawn that threatened to come up with a scowl. Despite his internal age, he was still, for all intents and purposes, in the body of an one year old, and without hunting down a good cup of coffee, his body needed rest. 

Reborn had never been one to deny himself before, unless it was for the job, be it woman, coffee, or entertainment. _Tsunayoshi wasn’t going anywhere and a nap wouldn’t hurt anything. He would call later._

* * *

__

Skull was riding a bus out of Bangkok towards China when his phone went off. He quickly pulled off his helmet. 

_You are my sunshine, my only—_. 

Skull snickered even as the people next to his stared, answering his phone. “Hey Senpai!” he teased. He could practically hear Reborn’s teeth grinding at the title. “What can the Great Skull-sama do for you?” He opted for Japanese, though he was a bit curious to why Reborn was calling him. Reborn _never_ called him. The hitman even ignored half his calls unless he called several times in a row. 

“Lackey, where are you?” Reborn ground out. 

Skull blinked, his ears twitching in surprise. He pulled the phone away from his ear to make sure it was Reborn’s number on the screen. It _looked_ right, and the person on the other end certainly _sounded_ like Reborn. 

He tentatively placed the phone back against his ear. “Reborn, are you okay?” he asked carefully. 

“ _What,_ ” Reborn growled darkly, or at least tried. Baby voice took away at _least_ thirty percent of Reborn’s intimidation factor. The lisp was kind of adorable. Plus, Reborn’s intimidation factor relied heavily on being face to face. 

“Well,” Skull drawled, still kinda worried but not missing the opportunity, “You _never_ ask where I am. Or call me. Or answer any of my phone calls. Frankly, Reborn, I’m under the impression you want me to stay as far away—” 

“Skull!” Reborn snapped. _Oooh, Reborn was **not** in the mood for sass,_ Skull thought with a snicker. He should probably stop messing with him though. 

“I’m in Thailand!” Skull says cheerily. He was on his way to see Fon and hang out with the only shifter in his pack. 

He waited for Reborn to respond, tapping his fingers on the octopus decal on his helmet crest. “... Why are you in Thailand?” Reborn asked in the stilted way that spoke of disbelief. 

Skull shrugged. “I was visiting Mammon,” he said. Mammon was fun to hang out with if you got past their money grabbing tendencies, which was easy enough to do when he allowed them to be in control of his finances, and their jobs for the varia were always bound to interesting to tag along with. Mammon was practically his best friend at this point. 

“...Can you come to Japan,” Reborn said after a moment. Skull froze. He was legitimately worried about Reborn now. 

“Reborn... Don’t you have a job in Japan..?” Skull ventured, biting at his lip piercing. Mammon had mentioned it. _Something about training the Vongola decimo candidate..._ Skull thought. 

“How— _Mammon_ ,” Reborn growled before taking what could only be an attempt at a calming breath. “Yes.” 

Skull straightened in his seat, “Reborn, are you trying to ask the Great Skull-sama for ... help?” Skull said, trying to keep the humored tone from his voice. Given the sound of plastic cracking, he probably didn’t try hard enough. 

“... _Yes_ ,” Reborn growled. “All I can tell you over the phone is that this job requires your.. _unique_ skill set,” Reborn growled before hanging up. 

Skull snickered to himself as he ended the call on his end. _Reborn is always entertaining to talk to,_ he thought as he pulled up the encrypted messaging app he had talked, _nagged_ , Verde into making for the Arcobaleno, and tapped on Fon’s contact. 

> THEGr8SKL: hey, chAng of plans. 
> 
> **FON: Oh?**
> 
> THEGr8SKL: yep, Reborn needs my hlp. 
> 
> **FON: Reborn?**
> 
> THEGr8SKL: i knO rght?! he jst caLd me 
> 
> **FON: I see. Did he say for what?**
> 
> THEGr8SKL: no, bt he implyed wolfy stuff ... i tink 
> 
> **FON: Well, Contact me if you need help**
> 
> THEGr8SKL: SuR! Ill try 2 hang out @ a dfrnt tym 
> 
> **FON: It’s no problem.**
> 
> THEGr8SKL: TTYL! 

Skull smiled as he closed the app. Fon was probably his favorite of the Arcobaleno, after Mammon. Fon at least enjoyed hanging out with him, unlike some of his pack mates. Speaking of Mammon, Skull typed a quick message at the Mist Arcobaleno, telling them where they could find him if needed, before he put his phone away. He was pretty sure they had a tracker installed in his phone, as well as the whole snot divination thing they could do, but it was the nice thing to do. 

He pulled the backpack he had been using up onto the seat with him, unzipping it a bit. “Hey, Oodako,” he cooed softly, nudging the backpack. The bag wriggled for a moment before a red tentacle poked out. Skull smiled and allowed it to tangled with his fingers. “Reborn called, we’re going to Japan to see him an Leon.” 

A confused trill came from the octopus as it tugged his hand. “Reborn asked for help, he didn’t tell me for what.” 

Oodako trilled again, still sleepy from the job Skull had helped Mammon with. Skull smiled and rubbed his thumb against the tentacle tangled in his fingers. Oodako was his favorite creature in existence, other than himself, hands down. 

Oodako trilled a question, breaking Skull out of his thoughts, “Eh? Where in Japan?” Skull opened his mouth to answer, but... _Reborn hadn’t told him..._ “He didn’t tell me!” Skull yelled, suddenly frustrated with the hitman. 

A low rumbling growl worked his way out of his chest. He was going to track his stupid senpai down and give him a piece of his mind, or not. Skull wasn’t sure he wanted to give Reborn the satisfaction. 

That said, Skull was happy Reborn called _him_. 

It was... Nice. 

* * *

Reborn stared at his broken screen with irritation, a foreboding shiver crawling up his spine. _He was going to regret this._

**Notes for the Chapter:**

> The phone call is the same from uncertain terms. Except from Skulls point of veiw.
> 
> Also, The Arcebelano have been doing this for at least 20 to 30 years, but I retain the belief that Skull text like a teenager from 5 years ago.


	3. Wolf enters stage right

**Summary for the Chapter:**

> Skull is finally in Namimori, if Reborn's reading these texts right. Who still uses Texting lingo these days anyways.

**Notes for the Chapter:**

> Beta'd by [JustAnotherOutcast](http://archiveofourown.org/users/JustAnotherOutcast)

The only warning Reborn got for Skull’s _possible_ arrival was a string of increasingly indecipherable texts over the past two days that were accompanied by both frowny faces and exclamation points. At one point Skull just sent a picture of himself flipping the camera off, the caption saying ‘ _Fek U_ ’. Needless to say, the only thing he could parse from the messages was the fact Skull was _not_ happy with him. The stunt man had managed to convey threats ranging from burning his fedora to just abandoning him to hang out with Fon. _Though I might be misreading them,_ Reborn mused as he picked up the file he had gathered about Namimori.

It turned out that the Hibari Nana was talking about was a battle hungry first year high schooler who ruled over Namimori as both the leader of a yakuza-esque group called the disciplinary committee and as the top ‘shifter’ of the territory. Despite having aged out of Nami middle, the shifter had made the school his headquarters in a way that screamed cloud flames to Reborn. 

That plus the meeting he had endured with the _definite cloud_ only helped solidify it. A shiver tried to run up his spine at the memory. If Hibari Kyoya wasn’t related to Fon in some way or form he’d burn his fedora himself. The shifter had all of Fon’s predatory presence with none of the martial artist’s restraint. Reborn had walked into that room and felt almost like prey for most of the meeting, not that he showed that in any way. The shifter tried for him several times during the meeting, and his eyes seemed to shift from gunmetal grey to gold repeatedly. 

Nana broke his thoughts as she placed a cup of coffee next to him with a hum as she passed. Reborn spared her a glance as he picked it up. Her mood had risen to sunshine-esque levels at the confirmation of Skulls arrival. He had also reassured her that his presence meant that the _numerous_ assassins that were apparently gunning for the vongola heir, _Iemitsu_ , would back off. 

He took a sip of the simply divine coffee before going back to the information in front of him. There were three of the many reconned files of the Namimori citizens spread in front of him on the kitchen table. They were the three Reborn was considering for future guardians once Tsuna was capable. All of them around Tsuna’s current age range with strong enough flames. 

The first was one Yamamoto Takeshi, Ace of the Baseball team with strong untapped rain flames. Shows signs of severe depression and natural hitmen talent. ( _His eyes had drifted to Reborn’s less obvious hiding spots several times and Reborn could see how he adjusted his grip on the bat everytime Reborn was close_.) Not to forget the obvious mental and physical strain baseball is doing to him. Possibly suicidal, but easy to manipulate to the sky’s side with the proper planning. He would keep an eye on him and hope the baseball star’s eventual mental breakdown happened after Tsuna was human again. 

The second was one Sasagawa Ryohei, captain and founder of the middle school’s boxing club, and older brother to the first year’s idol Kyoko. The boy leaked sunflames with the same amount of battle lust that Hibari radiated, though the boxer channeled it to boxing instead of fighting any strong opponent that crossed his pass. A second year in middle school but attends all of the third year classes with no real difficulty. Little to no manipulation needed, some physical prowess thrown around and use of the boy’s natural airheadedness would make it easy to sway him to Tsuna’s side. _He’s not entirely unwilling to believe that Tsuna could probably attract him a lion._

The third was Hibari. The obviously strong cloud flames the boy possessed mixed with the fact having another shifter might be beneficial to Tsuna if Verde’s info is to be trusted. Shifters that usually worked in groups tended to gather both humans and shifters to their side, not unlike a Sky-flame user. If, _a big if_ , Tsuna beat the panther prefect of Namimori, he might be able to sway the cloud with the promise of strong enemies to fight. 

He gave his nice, concise profiles away with a sigh. Nothing would come of his presence if Skull decided to suddenly ditch him or something. Skull owed him no real favors and, in what Reborn had figured out decades ago, had no loyalty to anyone who wasn’t a part of his pack. A part of him that wasn’t completely tininted in the darkness of the underworld knew that Skull didn’t think in terms of favors and debt like the mafia. Skull went where he pleased and was always willing to help out his pack members because he liked them. 

As if Reborn was summoning some sort of demon, his phone chirped with the first few bars of ‘You’re so Vain’ that meant Skull had texted him. He still wasn’t sure how Skull had convinced Verde to hack his phone to change all of his arcobaleno ringtones to _song puns_ of all things, but he couldn’t get past the encryptions the scientist had put on it. 

He opened the phone reluctantly, half expecting another garbled mess of random letters and numbers that was masquerading as a message. 

>   
>  THEGr8SKL: finalE found U (_o_). NXT tym teL ppl whr U R wen U ask 4 hlp. b ther s%n.  
>  **Reborn: what. **  
> ****THEGr8SKL: ...  
>  How do U not undRstNd txt lingo  
>  Lal duz  
>  pln wrds thN  
>  Look at your pacifier  
> 

**  
**  
****  


Reborn didn’t jump when he realised that his pacifier was indeed glowing the soft golden yellow of his sunflames, getting progressively brighter with each second he spent watching it. He calmly picked up his files and put them away in his suit jacket, the logic of it was almost impossible given that the files where bigger than his torso, but dying will flames tended to blur the lines of possibility.

He put the empty coffee cup down on the kitchen table before he jumped off himself. He would wait outside for the cloud; he wouldn’t put it past Skull to walk right past the house several times, and he wanted to make progress in this assignment. 

* * *

Skull walked warily down the street as he put his phone away, feeling rather naked without his biking leathers and helmet. He had traded them out for a soft lilac jumper and a pair of black shorts which were cheap enough that if he needed to shift, he wouldn’t have to risk the few precious minutes stripping. It also made people’s eyes skirt right over him. The combination of his childish clothes and the pacifier’s influence caused people to ignore his piercings and bright purple makeup, though he had replaced his white bandages with brightly colored band-aids. 

Of course, looking like a child didn’t help with the near constant presence of shifters and foreign cloud flames that permeated the very ground. 

He was in claimed territory in all the ways that mattered, and he could only hope that Reborn had told the shifter in charge that he was coming. He was in no mood to fight another shifter over a piece of territory he had no need for. He had his territory, and it was much more interesting than a piece of land. 

He stopped in front of a westernized house that smelt like a mix of cat, lion, and the familiar smell of _Reborn_. His amethyst pacifier glowed with a deep violet glow that confirmed that he had the right house. The house had a concrete privacy fence and a metal gate that allowed him a good view of both the front yard and Reborn standing in the doorway. 

... _Wait._

Skull blinked at the sight of the World’s Greatest Hitman staring at Skull like Skull had surprised him. It didn’t show on his face or was even barely noticeable in his body language, but Skull could understand more than enough non-verbal languages to be able to read Rebon. It helped substantially that he had known Reborn for thirty plus years by this point... 

The irritation he had been feeling for the past two days it took to hunt Reborn’s exact location twisted with the relief at finally having found his fellow Arcabelno. He smothered his impulse to grin as he jumped up onto the metal gate. _Thank you, weird Arcobaleno powers._ Here’s how he’s gonna do this... 

* * *

Reborn almost didn’t recognize the stuntman as he jumped down from the metal gate. Which was silly considering that out of them all, _with their adult mannerisms and completely coherent way of speaking_ , Skull was still the most recognizable Arcobaleno. A change of clothes shouldn’t draw his attention away from the very noticeable piercings and dramatic stage makeup the Stuntman seemed to apply religiously, despite wearing a helmet most of the time. In fact, by Skull not wearing his stupid helmet, Reborn should have recognized him instantly. Skull was the only person Reborn had ever seen with purple wolf ears in place of his human ones after all. 

Said ears were perked with what Reborn usually connected with excitement as Skull walked up to him, a carefully happy expression on the usually expressive shifter. Reborn focused on the shifter’s eyes, checking for the signs that the wolf was closer to the surface than usual. 

In most people, Reborn could pick up surface thoughts based off microexpressions and a general understanding of how people thought, but Skull and the rest of the Arcobaleno have used him as a sounding board for years to improve their poker faces. The seven of them were the only ones to have poker faces on his level, though they all knew each other well enough at this point that it didn’t matter. Either way, it looked like the wolf wasn’t at the forefront, so Reborn could talk to Skull without immediate risk of irate immortal wolves. 

The shifter closed the distance between them before Reborn could say much of anything, immediately ignoring him in favor of pulling his fedora over his eyes. “Hey, Leon! How’s my favorite Chameleon been doing?” the wolf chirped to the his partner. 

Reborn felt his eye twitch in irritation, hands curling into fists. “ _Skull..._ ” he growled, resisting the urge to sock the cloud in the stomach. 

“You did what? Haven't I told you to not to aggravate creatures bigger than you? Reborn can’t protect you from everything,” Skull scolded, apparently getting the low down of what happened from Leon. _He was perfectly able to protect his partner, thank you very much, he just couldn’t kill the decimo candidate_. Reborn wondered if it was just speculation based on the faint marks on the chameleons tail. Leon hissed at Skull who responded with chuckle. 

“That’s true, that’s true. The great Skull-sama apologizes that he doubted your humans great might.” 

Reborn felt mocked and was itching to shoot the shifter between the eyes, but he doubted he would come out unscathed. Skull would probably just take Leon if he tried to back up from his hold on the fedora. 

“Oodako had been really excited to see you again, but he fell asleep aft-” 

“Skull, I’m giving you the courtesy of a warning,” Reborn growled, cutting the wolf off, “ _Let go._ ” 

The shifter paused for a moment, debating his options. He ended up deciding to make the smart decision to not piss him off anymore, pulling the fedora back up with a practiced motion. Reborn scowled at him in a rare moment of displeasure as the wolf stepped back with a cheeky smile. _Reborn **did not** focus on how the dark purple of the stuntman’s lips looked stark and full against the bright white of his sharp teeth. The lazy way his left ear drooped was nothing close to endearing._

The wolf met his dark gaze with his bright violet eyes and brighter smile, “Heya Reborn.” the wolf greeted, placing a hand on his hip. “Can you tell me why you told me to come to Japan now?” 

Reborn stepped aside from the doorway, gesturing inside with a frown. “It’d be easier to show you, Skull,” he said, tilting his head enough to cast a shadow over his expression. 

Skull gave him a wary look before nodding. “You owe me for this Reborn,” the shifter stated firmly as he walked past him. “I could be eating dumplings with Fon right now.”

**Notes for the Chapter:**

> This chapter is a long time coming and I hope you guys are happy. I'm sorry it took this long but my muse was distracted by other things. Mainly college as some of you know. Chapter four shouldn't take as long, given that i actually know what i'm doing again. If Reborn seems a tad out of character that's because Skull's wolf is not intimidated by reborn. Especially not now that he's the size of a baby.


	4. Wolf in the lion's den

**Summary for the Chapter:**

> Skull meets the lion for the first time.  
> Tsuna meets the world's strongest Shifter.

**Notes for the Chapter:**

> Not beta'd this time, please point out any grammar errors you find. I'll fix 'em.

They lion pulled itself up suddenly, looking towards the steps to his den. It had gotten used to the feeling of the too small sun in the cat’s den and it’s own. One time the not-cub had come with the scent of the other feline, though it hasn’t gotten close to the lion after that first encounter. The not-club wasn’t the problem, it was the fact that the too small sun had been joined by a amethyst clouds compressed until it was denser than the air. _Tsuna wondered if the two sensations meant that owner of the presence was going to be similar to Reborn. He wondered if there was a not-cub that had the same warmth he did..._

_”You’re being unnecessarily dramatic, **senpai** ”_ an unfamiliar voice whined. The lion watched as the not-cub opened the door, trying to shake the uncomfortable feeling off. The varying sensations of things pressed far too small that weren’t meant to be confined grated against the lion’s senses. _Tsuna knew that it was unlikely the two meant harm now, though he was still unsure why Reborn was still here..._

_”Skull.”_ The not-cub threatened, gesturing at the stairs. 

_”Why do you want the great skull-sama to go down into the creepy basement that smells like blood? Are you finally going to off me?”_ The new voiced exclaimed with a gasp. The lion could hear the fear in the new one’s voice but there wasn’t any fear scent coming from the doorway. 

_”Skull, if I wanted to kill you, you’ve been dead a long time ago.”_ The not-cub stated, irritation radiating off of him. The lion shifted so it still had an eye on the doorway, but in a way so that it could also lie down. _Tsuna had a feeling this would take awhile...._

_”Ah ah. Don’t forget, I am the Great Skull-sama, the man hated by death itself.”_ The new one protested cheerfully. 

_”Don’t underestimate the World’s Greatest Hitman, Lackey.”_ The not-cub remarked darkly, the irritating green thing turning into a gun with a flash of light. _Tsuna wondered at how much the world has advanced while he was stuck down here if animals could change into things that weren’t humans. He thought the green th- the lizard had tasted weird._

_”Too bad you need me alive.”_ The new one laughed nervously. There was a long pause, neither of them talking. _” **Right?!** ”_

_” Go down the stairs and find out.”_ the not-cub ordered. The lion sat up again, watching the entrance to it’s den. Eventually the source of the folded cloud presence stepped through the doorway, freezing as their eyes met. _It did look like Reborn, a cub that wasn’t, Tsuna noted._

It was different from the not-cub. Where the not-cub was all dark coloring, gunpowder, and predatory, the new one was bright purple, the smell of sea salt, and purposely non-threatening. Were it not for the matching amethyst like pacifier, the lion would put them on different levels. _If Tsuna didn’t know better, he would think that Reborn was more of a villian from the old cartoons whereas Skull was just a strange civilian..._

Then the scent hit the lion, and it noticed the purple ears that were pressed against similarly colored hair. The duel scent was unmistakable and one that the lion never realized he was picking up off the not-cub. It was heady in a way that spoke of age and threaded seamless with the gasoline and sea salt one that was the human. 

The purple-cub’s eyes flickered with the familiar presence of another more wild side, not one the lion was familiar with but it was it much older that it’s owner. 

The energy that had been hanging in the air for the past few days hummed loudly, and a rolling purr rumbled in the lion’s chest. The ties of blood have come to rectify what they have ruined so long ago, and the world’s strongest shifter has come to help. 

* * *

Any amusement Skull might have gotten from messing with Reborn vanished the moment he saw what was actually in the creepy murder basement. _The smell of blood was heady even with the lack of any visible blood stains, it was totally a murder basement_. Suddenly he knew all to well why Reborn had called him for help, and why he had been so annoyingly vague other than because he was a sadistic asshole. 

Of all the things Reborn could have called him for, a shift locked shifter chained in a basement that smelt of _blood_ made a uncomfortable amount of sense. Skull’s whole skill set in the Mafia scene revolved around the fact he was a purple wolf half the time, even as an arcobaleno. He could even draw uncomfortable comparisons between the Decimo candidate and his own... _experiences_... 

He allowed himself to look over the poor kid, the part of him that is the wolf drawn to the surface by the presence of both Reborn’s too bright presence and the gapping lack the kid excluded. He also noticed how the kid smelt more like a lion than a human, smelling mostly of musty fur, pet shampoo, and old _human_ blood. It spoke of years stuck in the animal form and of protecting his territory. 

The juvenile shifter was something close to an African lion, from the beginnings of a amber brown mane to the tawny fur, the kid could pass for one. The amber eyes that glowed like flames and light color patterns that simmered in his fur not unlike Skull's own flickering fur coat said something different. He glanced at Reborn, not wanting to take his eyes off the kid in case something changed. Reborn was his go to mafia encyclopedia after Mammon, “Hey, Reborn?” He ventured. 

”Yes?” Reborn asked shortly. _Still a bit annoyed then_ , Skull brushed it off. 

”Can... This sounds silly but,”Skull said, his ears pressing against the side of his head at the very prospect. 

”Almost everything you say is ridiculous, but continue.” Reborn interrupted, annoying smirk in place. Skull rolled his eyes, he poked at the hitman’s nerves he got to deal with the petulance. 

”Right...Anyways, can someone, uh...” Skull started, unsure how to phrase what he was feeling from the kid. “Turn off their flames?” The very idea of it made something deep in Skull twist uncomfortably, because despite the fact they lead him to the life of organized crime they were such an intricate part of who he was. Flames practically saturated every cell in his body and they danced across his fur, the idea of being cut off from that... He shivered. 

Next to him, Reborn froze, a sudden tension snapping in between them. The _stupid_ fedora dark shadow covered any expression Reborn had. “What,” Reborn stated darkly, or as darkly as a baby’s voice could go, most of it really came from the killing intent that waffed off him like steam in a sauna. 

Skull bit at his lip nervously, “Can’t you feel the lack? You said everyone has flames, dormant or active. Even ‘civilians’ and shifters,” He recited looking at the lion who gazed back at him. There was definite human intelligence behind the bright amber gaze. “That lion doesn’t have any. It’s just like this cold _void_. Like the vindice but worse.” His tone was quiet near the end, the vindice freaked even Reborn out. _Deep down he remembered meeting people who reeked of death and hatred so potent he almost puked, of the chilling words that nearly sent him into his shift. **Do not break Omérta.** Skull, despite his overwhelming cloud flames rarely manifested them physically, even as a wolf_. 

Reborn was silent for a long few seconds, his tense stance reflecting the apprehension Skull did. “Are you sure?” Reborn said suddenly, his tone unnatural calm and steady, the sound sent a shiver down his spine. 

Skull felt the instinctual unease build behind his collarbone, his own flames, that were so tied with the wolf, recoiled from the void the lion _wasn't_ leaking. “Skull-sama is pretty sure,” He said quietly, the unease pressing against his handle on the human parts. _The lion was so **young** , he couldn't even begin to wonder what that meant for reintegration into society. Not even covering what it meant to be cut off from a part of your **soul.**_

Reborn was quiet for an uneasy amount of time, before he spoke, “Fuckin’ Iemitsu,” Reborn growled under his breath, quiet enough that only Skull could really hear, before turning to Skull. “To answer your question lackey, yes it's possible to seal off someone's flames,” _The dread that rushed through Skull cut him down to the bone, an aborted motion was made to grasp at the pacifier shaped object that hung around his neck._ “But only the Vongola skies have the knowledge on how to do it, and only skies can do it, at least in the mafia.” That didn't mean safe, Skull knew, not when they were training the heir. Not that they had many flames not being sucked by stupid vampire pacifiers left. Skull wasn't bitter. Not at all... 

Skull glanced at Reborn again, the hitman's face impassive. “Doesn't that mean the Vongola ninth did this to the kid? I thought Nonno was one of the better ones?” Skull asked, He was pretty sure there was only one sky still in power in Vongola and he knew what happened to Mammon’s boss. 

“More than likely, but that's just how the Mafia works. A threat is better neutralized until it's useful to you. A young vongola sky when there were already four viable heirs?” Reborn confirmed in the same blank voice, anger bordering on rage leaking into his scent. He didn't finish his sentence, allowing Skull to finish it in his head, _Get rid of the extra civilian_. Skull counted back the years of the Vongola heir death timeline in his head, using his fingers as to not to count. Federico’s body had been found not to long ago, and Enrico had died in that gunfight about five years ago... 

He stared at his hand, any sort of academics were more Verde and Reborn’s thing, but his math was good enough. Take in the fading human smell on the lion that wasn't his mother or Reborn... “He took the flames away from a _five year old flame active?_.” Skull hissed in a mix if horror and protective anger. His wolf felt like it was just seconds away from making itself known, the beast that was still him roiled under his skin. 

Reborn gave him a grim nod, his own eyes still on the lion. “Nana says that Nonno and Iemitsu visited them when Tsuna was around five, she’s not quite sure what happened but she thinks Tsuna fell from the tree in the backyard. Tsuna probably got spooked and his flames manifested to break his fall. Nonno got there first.” Reborn said, looking at Skull. “Iemitsu handed her Tsuna as a lion cub and said he got spooked by the dog next door.” 

”And Tsuna never shifted back? Even when he fell asleep?” Skull asked, he looked at the relaxed form of the lion. He glanced pointedly at Reborn before tilting his head towards the stairs in askance. The hitman nodded minutely as he mulled over Skull’s question. Skull looked back at the lion as he started down the stairs. He tried not to think to hard about the fact the smell of blood got stronger with each step. 

”Not to my knowledge, shifting is easier when the person’s relaxed?” Reborn questioned, Skull could feel his gaze on him though not maliciously. 

”Adrenaline can be a trigger for some shifters.” Skull said absently, almost half way down the stairs. “Especially young ones.” 

”What’s yours?” Reborn asked calmly enough, a very good attempt at nonchalance, but Skull _knew_ Reborn. Reborn really wanted to know for the fact knowing would give him the ability to control the situation. Like hell was Skull answering that question in any real sence. 

”Not adrenaline, otherwise the great Skull-sama wouldn’t have been so great.” Skull deflected with a cheery tone. “If you didn’t ignore me all the time you’d probably know.” He added under his breath, the lion’s eyes still tracking his decent. 

“What was that lackey?” Reborn half demanded, still maintaining his calm tone. 

”The lion’s staring is creepy.” Skull replied, almost at the bottom of the steps at this point. The lion levered itself up in long smooth motions, it’s eyes still on him. He could feel Reborn stiffen at the top of the stairs in a mix of apprehension and anger, his eyes no longer on Skull. 

”...Be careful.” Reborn muttered, almost too low to hear over the dragging of the lion’s chain as the beast padded up to Skull. On the third to last step he was almost level with the lion’s head, given his own miniscule height. Skull vaguely wondered how scared Reborn had been when the Lion had pounced on him to get Leon. A disadvantaged human who was used to being most terrifying person in the room confronted with someone who was barely more than a cub. 

He held a hand out for the lion to come to if it wanted, treating it like the wild animal that was at the forefront. “No one can hurt the Great skull-sama Reborn.” The lion padded even closer and pressed it’s nose against his tiny palm, an acceptance for interaction. Skull looked into the lion’s eyes again and saw the glimmer of the kid the lion still was. He ran his hand across the lion’s muzzle, rubbing his hands lightly over the coarse fur. “Hey lion cub. I am the Great Skull-sama and I’m gonna help you, Reborn too. We’re going to give your flame back to you and make sure no one can take them from you ever again.” Skull smiled at the cub as he whispered the promises. Promises he was planning to keep.

**Notes for the Chapter:**

> I apologize if it seems rushed, I really want to get into the cannon stuff and I couldn't do that if Tsuna is still stuck. Please comment with questions or anything.

**Author's Note:**

> Please comment with any questions you want clarified the story. I am willing to answer to a degree. (i honstly dont know what people would want to know that i didn't already cover in other fics or spoils the future chapters...)


End file.
